This invention generally relates to the art of digital imaging. The invention finds particular application in adjusting for image errors or artifacts induced by a lens array employed to either scan physical images into an image representation, or to output image representations onto physical media. It is to be appreciated however, that the present invention finds further application in other imaging devices with spatially varying error or artifact functions.
Image acquisition devices, such as scanners, and image output devices such as printers or copying machines, typically employ a lens mechanism to either transfer a physical image onto a photo sensitive surface in the case of an image input or scanning device, or transfer a digital image representation onto a hard copy or physical output media.
Indeed, certain optical systems used in image reading or writing possess a spatially varying point-spread-function (PSF). An example is the local blurring and image doubling that occur due to tilted rods in a Selfoc® lens array. This local PSF effect can cause severe streak artifacts in scanned and printed images, particularly halftone images. In many input scanners, scan bars are rejected due to this problem. This defect and other array lens defects vary across the field, hence, a restoration or pre-compensation based on the traditional assumption of a spatially uniform PSF do not yield satisfactory results.                present invention contemplates an improved method and apparatus to correct or adjust for errors in an optical system using image post-acquisition and pre-output techniques which overcome the above-referenced problems and others.        